Effects Of Carbon,Nitrogen Addition And Dry-Wet Alternations On Litter Decomposition Of Robinia Pseudoacacia Forest In Dump Site

In this study,the leaf litter of robinia pseudoacacia plantation in the dumping ground of haizhou open pit mine was taken as the object of study.The leaf litter was treated with C addition?5 gradients,with glucose as the medicine?,N addition?5gradients,with ammonium chloride as the medicine?and wet and dry alternately?3gradients?by the bag decomposition method.C and N added research to add not litter for control of C and N,dry-wet alternate research and humidity treatment litter as contrast,the litter decomposition rate?quality retention rate?,nutrient index?C,N,P and residual lignin rate?and the stoichiometric value?C/N,C/P and lignin/N?were determined and analyzed.The results show that:?1?the addition of high C(7.5g C.m²·a^-1)and high C(10g C.m²·a^-1)had no effect on the decomposition of litters,while the addition of low C(2.5g C.m²·a^-1)and medium C(5g C.m²·a^-1)inhibited the decomposition of litters,thus slowing down the material circulation and energy flow of the ecosystem.The addition of C inhibited the release of C and lignin elements from litters to the soil,thereby reducing part of the soil nutrients and reducing the source of plant root nutrients.?2?the addition of low N(3g N.m²·a^-1)and high N(24g N.m²·a^-1)had no effect on the decomposition of litters,while the addition of low N(6g N.m²·a^-1)and high N(12g N.m²·a^-1)promoted the decomposition of litters,thus accelerating the material circulation and energy flow of the ecosystem.The addition of N promoted the release of C,N and lignin elements from litters to the soil,thereby improving part of the soil nutrients and the source of plant root nutrients.?3?wet and dry alternately inhibit the decomposition of litters,thus slowing down the material circulation and energy flow of the ecosystem;The alternations of wet and dry inhibited the release of litter to soil C and lignin,thereby reducing part of soil nutrients and the source of plant root nutrients,but the effect was of short-term and delayed nature.In short,C added and dry-wet alternate inhibits litter decomposition,N add promoted the litter decomposition,through the C/N,C/P and lignin/N can't predict the litter decomposition process,but lignin can well predict litter decomposition process,this study of open-pit mine reclamation field soil improvement and provide a scientific basis for reasonable operation and management.This paper has 27 pairs of figures,9 tables and 146 references.